Modern Classic SLRs Series :
Nikon FM2(n) - Other Issues Part IV

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A LED match-diode meter display system is employed inside any of the FM2 models and there are 5 combinations in its display to indicate status of metering.


User's Tips: In most cases, it is quite difficult to obtain just the (o) correct exposure indication. Chances are higher that you may constantly seeing (+o) or (-o) glows inside the display which suggest the exposure may be out for about 1/5 to less than a stop which is not significant if you are using negative film. For exposure-latitude-tight slide film, it is still within safe tolerance for a correct exposure.

LEDs display was very popular during the '70 and for most part of the early '80. Although technically, LCD display has a distinctive advantage over LEDs in energy saving (It consumes only 1/10000th of power compared with LED); but LED has superior contrast and provide excellent visibility in low contrast or low lit situations.

The clue is: UNLESS you have all the time in the world to do fine tuning of exposure to get it right (o) via aperture on the lens (But NOT by adjusting through shutter speed), I would always encourage you to capture the image first and give it a bracketing exposure later. Frankly, chances of spoilt exposures are higher for an inexperienced lab assistant that handling your prints rather than you are worrying LEDs indicators inside the viewfinder could mislead you for an exposure error,

The metering circuit is comprised of two silicon photo diodes (SPD) positioned near the eyepiece, which has enhanced the stability of FM2(n) TTL exposure metering system. Why ? The Nikon FM is using a pair of gallium photo-diodes (GPD) to power its meter while the newer FM2(n) utilizes a far more superior SPDs. However, the metering range performs only fairly , extending from of EV1 to EV18.

The official published figure was almost made as a "Nikon standard" for most of their SLRs stretches throughout the mid '70 to early '80. The LED match-diode meter, I think it was first used in the Nikon F2SB was a more logical choice over match-needle system for mechanical camera. The current entry level model, the Nikon FM10 also uses the similar LED match-diode of the FM series.

* OFF TOPICS Supplements: Over the years, Nikon has known to have used a few types of metering cells for their manual focus SLRs, namely: Cds, SPCs, GPDs and SPDs. Photocells generates varying electrical characteristic (e.g. current, voltage or resistance) when light is incident upon them. However, first batch of Nikon SLR uses Cds (Cadmium Sulfide (Cell) for the Finders (in the case of the Nikon F and the later Nikkormat). Cds is a light dependent resistor rather than a cell, it is current-modulating light-sensing cell that was quite popular with lots of older cameras exposure metering system and external metering devices. However, it does not generate electrical current when lights hits them as with SPCs. Instead, current is being allowed to pass through the circuit when light hits the resistors. Later Nikon SLR models used SPC or GPDs which has a far superior light reacting characteristic than Cds. Silicon cells is a light-sensitive substance which generates a minute current when exposed to light. They change the light energy into electrical current and amplify by batter circuit to a usable level for metering application. Both are very sensitive to light with the Gallium Photo Diode without the need for filtration in infrared light levels. Most modern Nikon SLRs use SPD for their metering circuit as Nikon explained SPD cell maintains a far more stable performance. But a more realistic answer could be, silicon based cells are generally less costly despite cells constructed from gallium arsenide are in principle more efficient as compared. Within my limited knowledge, that is all I know about metering cell.

View.jpg View.jpg
While the exposure information uses LEDs display, Nikon also incorporated a welcoming feature of viewfinder ready light first used on the Nikon F2A/AS and Nikon FE to the new FM2 in 1982.

Technically, the flash ready-light should work with any Nikon flash that has the standard ISO type flash mounting foot that comes with additional terminals other than the main flash sync contact at the center. Popular modern AF and Manual Nikon speedlights such as SB-10, SB-E, SB-15, SB-16B, SB-18, SB-19, SB-20, SB-22, SB-23*, SB-24, SB-25, SB-26, SB-27 can be attached to any of the FM2 series models, and the useful built-in LED ready-light will tell you when the Speedlight is recycled and ready to fire or when the shutter speed is set outside sync range, without your having to remove your eye from the viewfinder.

Hotshoe.jpg The extra contact atop the accessory shoe is the flash ready light contact. Where a dedicated Nikon flash is attached and stay in contact with the ready light at the flash mounting foot.

| More info on Other Nikon Flash Units |

I am not questioning such unpopular decision made by Nikon but I think it is totally unnecessary if such move was purely market driven. Neither any of those flash units have clear explanation how the flash will behave if it was used on a Non-TTL flash capable camera body.
 * Theoretically, ANY flash unit made by Nikon should able to find a way to use on any Nikon FM series camera models either via direct mounting, flash coupler or cable connections. However, with the advent of autofocus revolution and in particular TTL OTF flash exposure control used in most modern SLR bodies, there are a small number of flash models strangely omitting the basic requirement of Auto and Manual flash control. Technically, I would assume even if a flash was made to be only AF/TTL-only and if it is used in a camera such as FM2(n), the flash will still fire at a default output setting as long as there is a electrical connection beween both two main flash contact on the flash mounting foot as well as on the camera body section mate.

If you have any specific finding relates to this particular issue, you are free to mail in your experience or make use of the | Message Board | to publish your findings.

Note: (A): X-sync; (B): Flash Ready light Contact.

Ready Light Status Per Shutter Speed Dial Setting

Shutter Speed Dial Setting

Flash charging complete

Flash charging NOT complete

1/4000 sec. ~ 1/500 sec.



1/250sec.~1 sec.

Lights up continuously



Lights up continuously


Notes: 1) No matter how the shutter speed dial is set, the Speedlight will fire when the ready-light is on the moment the shutter release button is depressed. 2) The ready-light will function regardless of whether the camera's exposure meter Is on or off; 3) When the camera's exposure meter is on, the LED exposure display Inside the viewfinder shows the exposure condition of the moment regardless of whether or not the flash fires. If the shutter speed is set at B, the LED exposure display will not be activated.

models* within the FM2(n) series have straight forward mechanical simplicity. The FM and FM2(n) models' basics are of very high quality. In fact, personally, I felt the Nikon FM's hard chrome plated body shell exhibits a kind of elegant that is even hard to duplicate by the newer chrome FM2(n) bodies. But you do not have to worry about its reliability because the FM2(n) bodies do have a solid die-cast chassis to protect the internal mechanism and its electronic metering circuits. * Except the entry level Nikon FM10 which I still have some personal reservation over its dependability for heavy duty photographic usage. I would believe the FM2(n) bodies will endure the most rugged treatment , if it doesn't - I doubt many other modern AF SLR cameras which claimed to made of "industrial grade" plastic can survive either.

The two-pieces FM2(n) chassis is made out of an exceptionally strong and corrosion resistant Copper Silumin aluminum alloy which has a metal characteristic of a tensile strength of (33.5kg/mm2).Note: I am not an engineer, my MCLau is one. However, he commented: "... Tensile strength of seems low to me, Steel has a tensile strength of 40,000 ib/in2....". IS there anyone out there who can comment further ? The first input:

Subject: Tensile strength of FM2
From: "Ho, Wai-Ming" <>
To: <>
Cc: <>

hi, i m not a materiels engineer but my other engineering training teaches me that 475lbs/in2 alone doesn't say a lot about an alloy. some aluminimum alloys of 457lbs/in2 are used in master brake cylinders and engine valves. just remember that pure strength is useless if it rust...and too heavy. it only needs enough of it to protect from occasional accidental abuse. it is not suppose to be drop from the top of KLCC :o) btw, good engineering is about designing for equivalent failure limits for all existing constraints. after all, it's the weakest link that breaks first. the rest is irrelevant. just like having the best shark fin cooked in a soap that's too salty. best regards, wai ming

ps: 475 lb/in2 = 0.335 kg/mm2, not 33.5 kg/mm2 on the web. perhaps you meant 33.5 kg/cm2 ? pps: interesting way of presenting your web. effective psychological filtering.

The minimum thickness of the body walls is 1.4mm, and near the F-bayonet mount is a robust 2mm thick to enable it to take on the heaviest Nikkor lens in handheld position ! *

* Despite of what it claims, it is always encouraged to make use of any built-in tripod collar on the lens with such lenses, where most sizable Nikkor lens usually comes with a built-in tripod mount on the lens barrel.

The body is further treated with black Alunite and coated with another layer of black paint for added corrosion prevention. Even the standard film back is made of the same high grade aluminum alloy as the body while the all important top and bottom covers of the camera are made of brass !

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The famed F-mount has been around to serve demanding professional photographers over the last few decades with full confidence. Although it has has been taken for granted, but it is essentially one of the few worthy technical highlights of the FM2n.

Big, heavy lenses such as this bulky AF80-200 f2.8 ED may demand a good support. The high quality lens mount may prove critical to photographers such as those actively involving in news, reportage, sports arenas etc who are quite fond of carrying big lenses mounted onto cameras. IF that is not enough to meet your specific specifications for a particular important assignment that may expect even higher degree of durability, Nikon did produced a version of the FM2(n) body which made of Titanium in 1994. The Nikon FM2n/T is a special version of the Nikon FM2 camera, uses titanium exterior covers (top and base plate). Titanium is one of the world's strongest yet lightest materials; its specific gravity is approximately half that of brass, yet it is hardness is almost the same as that of steel, while its corrosion resistance is greater than that of stainless steel. The use of such genuine Titanium material enables good protection of its internal precise mechanisms against external shock and hard knocks. Along with a stable and high performance shutter unit inside the protective covers, this makes FM2n/T one of the toughest SLRs you can find around on the market. The specifications of FM2n/T is the same with the normal FM2n except its finish and in the weight.

The mirror box mechanism has some unique improvement too. There is a patented controlling gear and control wheel where it helps a great deal in minimizing vibration and bounce in mirror movement to absolute minimal level.

Additionally, foam rubber in the spring coil also was incorporated aims to minimize sound level which along with cushions inside the mirror box, together they are designed to reduce noise and absorb shocks and bounce. The mirror frame, made of tough and long lasting Titanium ensures lighter, smoother movement, even under constant poundings and heavy usage with automatic film advance device such as the motor drive MD-11 or newer MD-12. All these refinement made couples with an improved efficient low-torque film transport system employed earlier from the Nikon FM/FE provides meticulously smooth film winding for all the FM2 series models. With such high grade ball bearing clusters, a large pressure plate and long, polished guide rails ensure extra smooth and precision movement of film whether it is manually advanced or by motor-driven. Such efficiency enables the FM2 series models present a level of operational ease that is hard to match in any other SLRs among its class.

FM2 Back.jpg (18k) Loading...
By the way, I have notice very few FM2(n) with rusty film guide rails, have you ? Nikon claims it uses stainless steel for that section. However, the winding mechanism was not designed to permit multiple short strokes as with the Nikon F3. But Nikon has always enjoyed a fine reputation for its smooth and efficient film advance operation.

Just for an instance, Its power efficiency is a top rated 100 rolls of films when used with a MD-12 with just per set of eight (8) alkaline cells, thus, the breakdown cost per frame is minimal. While as a basis of comparison, Canon Motor Drive MA can go only 60 rolls with a set of twelve (12) Alkaline cells !
Technical: Film advance lever torgue with film uploaded at 2.0kg/cm or less; film loaded is a higher 3.5kg/cm or less. The Spool has a torgue of 90-140g/cm with slipping loadbetween 144-224g as service standard. If you camera experienced "overlapping" images, check if the base section of the spool has came loose. It is not usual for this to happened, but just in case you are in a remote area, may be you can fix it yourself with a super glue or anything to temperarily solve the problem first but I would still strongly sugest you to send back the camera for proper fixing after that.

Some other nifty features found on the FM2 can often help you become more productive (and creative at times...) should you are more familiar with their respective usage. Although most of which are not that commonly used, but they are here should you need them.

The symbol just next to the pentaprism on top of the camera body is the film plane index. It is precisely engraved at a distance of 46.5 mm from the front of the lens mounting flange. While today's Nikon's system accessories for macro photography, it was a hardly used feature. But for those whose works demand a exacting measurement this feature is placed for that reference.

Memo holder. Whenever you change rolls make use of the memo holder. Just slip the top of the film box into the FM2's memo holder. In this way, you'll always know exactly what kind of film you're using and how many exposures you have.

Naturally, you can make use of it to put a custom made name card or contacting info during traveling Since none of the FM series models have Auto Film Speed Indexing, it may come in handy.

PC Terminal.jpg
In front of the FM2 camera body, there is a PC sync terminal (in most cases, it should shield with a protective cap). It creates contact between camera and flash via cable or cord connection. It also acts as an X-terminal for some older types of flash bulbs (It synchronizes with M, FP flash bulbs at shutter speeds of 1/30 second or below ('B' setting included).

Note: In the case of using older Databack MF-12 with FM2(n), you would need to plug in the cord from the film back to this socket. * In any case, the maximum sync speed with either Nikon made of third party flash SHOULD not exceed the maximum permissible sync speed of the respective camera provides. i.e. 1/200 sec for original FM2 and 1/250sec for FM2(n) models. However, you can use this setting with slower speed, including "B" for long time exposures and open flash technique.

Some non-TTL Nikon flash units have some very useful features such as this SB-15 which has a PC terminal built-in. Although one would expect it could incorporate both the TTL sync terminal and PC terminal but that remained as an exclusive feature on only a few "highend" models such as
Nikon SB-17 and SB-16A/B.

This enables Nikon FM2 to extend its working capabilities on multiple flash setups via sync cords or cables but since the camera body does not support TTL flash, you can make use only the AUTO or full manual flash control. May be a little OFF TOPIC but a good general knowledge for you. Wondering how the frame counter reset to "0" each time the film back is opened ? The trick is a tiny spring behind the metal piece hide inside film back railing.

The film back has a small protruding edge that will stay in contact when the film back whenever film back is closed. Once the camera back is opened, it will trickle a mechanism to the frame counter and reset its value back to "0".


Nikon improved the film changing process for both the mechanical Nikkormat and Nikon F2' with a new way of opening camera back with the electronic Nikkormat EL in 1972. Subsequently, all manual focus Nikon bodies (Except the DX coded Nikon F301) shared similar method.

It is a double action process with a safety lock incorporated, in order to open the film back, you ought to use a finger to push the lever (as shown in arrow) before you lift the film rewind knob upward. The film back will spring open. OFF TOPIC Supplements: Wondering how the aperture value you selected on the lens being transmit and shown atop inside the viewfinder display ?

The trick is the ADR window just underneath the "Nikon" name inscribed in front of the pentaprism which transmits the aperture value in use to the viewfinder inside.
AF lens.jpg

BUT it needs a minimum AI-modified spec Nikkor lens to work (which has a meter coupling ridge and ADR scales engraved on the aperture ring). Shown at left is a manual focus Fisheye Nikkor 16mm f/2.8 lens and an AF Micro Nikkor lens at right which both has the AD scales on the aperture ring.

ADR.jpg ADRillus.jpg
Illustration of optical path for ADR (Aperture Direct Readout) and shows how it works inside a Nikon SLR camera.It is not based on a Nikon FM2 here in this diagram, but with a F3. The principle, however, remains the same.

| Previous | Next | Other Issues Part IV (3/5 parts)

| Back | Index Page of Nikon FM2 models
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Full Specifications: Main Reference Map : HTML | PDF
Nikon FM2n's Instruction Manual is ONLY available in HTML format (6 parts)

Standard production Nikon FM Series models:- Nikon FM | Nikon FM2 | Nikon FM2n | Nikon FM10 | Nikon FM3a |
Known variants:- Nikon FM Gold | Nikon FM2/T | Nikon FM2N Tropical Set | Nikon FM2/T Limited Edition | Nikon FM2N LAPITA | Nion FM2n Millennium 2000

| Message Board | for your favourite Nikon FM Series SLR models
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Shared Resources: MD-11 | MD-12 | Focusing Screens | Titanium Shutter | Flash Units -SB-16 | SB-15 | SB-10 or other Options | Databack | Nikkor lens mount (related info)

Others:- Nikon AF-TTL Speedlights | SB-20 (1986) | SB-22 (1987) | SB-23 | SB-24 (1988) | SB-25 (1991/2) | SB-26 (1994) | SB-27(1997) | SB-28 (1997) | Nikon SB-29(s) (2000) | Nikon SB-30 (2003) | Nikon SB-600 (2004) | Nikon SB-800 (2003) Nikon AF-TTL Speedlight DX-Series: Nikon SB-28DX (1999) | SB-50DX (2001) | SB-80DX (2002)

Nikon BC-flash Series | Original Nikon Speedlight
SB-2 | SB-3 | SB-4 | SB-5 | SB-6 | SB-7E | SB-8E | SB-9 | SB-E | SB-10
| SB-12 | SB-14 | SB-140 UV-IR| SB-15 | SB16A | SB-17 | SB-18, SB-19 | SB-21A (SB-29) Macro flash | Flash Accesories | SF-1 Pilot Lamp

Instruction Manual: Nikon FM (HTML | PDF) | Nikon FM-10 (HTML) | Nikon FM2n's User's Manual available only in HTML format (6 parts) | Nikon FM3A (HTML)
Nikon FM, FM-10, FM2, FM2n and FM3A / Main Reference Map: (HTML) Nikon FM, FM2, FM-10, FM2n (Applicable to FM2T, FM2 "Year of the Dog"; Millennium 2000") and Nikon FM3A

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Nikon Auto Focus Nikkor lenses:- Main Index Page
Nikon Manual Focus Nikkor lenses:- Fisheye-Nikkor Lenses - Circular | Full Frame | Ultrawides Lenses - 13mm15mm18mm20mm | Wideangle Lenses - 24mm28mm35mm | Standard Lenses - 45mm 50mm 58mm | Telephoto Lenses - 85mm105mm135mm180mm & 200mm | Super-Telephoto Lenses - 300mm 400mm 500mm 600mm 800mm 1200mm |

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Index Page
  Special Application lenses:
Micro-Nikkor Lenses - 50mm~55mm -60mm 85mm -105mm 200mm Micro-Zoom 70-180mm
Perspective Control (PC) - 28mm 35mm PC-Micro 85mm
Dedicated Lenses for Nikon F3AF: AF 80mm f/2.8 | AF 200mm f/3.5 EDIF
Depth of Field Control (DC): 105mm 135mm
Medical Nikkor: 120mm 200mm
Reflex-Nikkor Lenses - 500mm 1000mm 2000mm
Others: Noct Nikkor | OP-Nikkor | UV Nikkor 55mm 105mm | Focusing Units | Bellows-Nikkor 105mm 135mm
Nikon Series E Lenses: 28mm35mm50mm100mm135mm | E-Series Zoom lenses: 36~72mm75~150mm70~210mm

MF Zoom-Nikkor Lenses: 25~50mm | 28~45mm | 28~50mm | 28~85mm | 35~70mm | 36~72mm E | 35~85mm | 35~105mm | 35~135mm | 35~200mm | 43~86mm | 50~135mm | 50~300mm | 70~210mm E | 75~150mm E | 80~200mm | 85~250mm | 100~300mm | 180~600mm | 200~400mm | 200~600mm | 360~1200mm | 1200~1700mm

Tele-Converters: TC-1 | TC-2 | TC-200 | TC-201 | TC-300 | TC-301 | TC-14 | TC-14A | TC-14B | TC-14C | TC-14E | TC-16 | TC-16A | TC-20E

Recommended links to understand more technical details related to the Nikkor F-mount and production Serial Number: by: my friend, Rick Oleson by: Hansen, Lars Holst

W A R N I N G: The New G-SERIES Nikkor lenses have no aperture ring on the lens, they CANNOT ADJUST APERTURES with any of these manual focus Nikon FE series SLR camera models; please ignore some portion of the content contained herein this site where it relates.

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Credit: To all the good people who has contributed their own experience, resources or those who are kind enough granting us permission to use their images appeared in this site. Mr. MCLau®, who has helped to rewrite some of the content appeared this site. Chuck Hester® who has been helping me all along with the development of all these Nikon websites;LarsHolst Hansen, 'Hawkeye' who shares the same passion I have; Ms Rissa, Sales manager from Nikon Corporation Malaysia for granting permission to use some of the official content; TedWengelaar,Holland who has helped to provide many useful input relating to older Nikkor lenses; Some of the references on production serial numbers used in this site were extracted from Roland Vink's website; HiuraShinsaku from Nikomat Club Japan. t is also a site to remember a long lost friend on the Net. Note:certain content and images appeared in this site were either scanned from official marketing leaflets, brochures, sales manuals or publications published by Nikon over the years and/or contribution from surfers who claimed originality of their work for educational purposes. The creator of the site will not be responsible for may discrepancies arise from such dispute except rectifying them after verification."Nikon", "Nikkormat", "Nippon Kokagu KK" & "Nikkor" are registered tradename of Nikon Corporation Inc., Japan. Site made with an Apple IMac.